Drug solubility has been a common limitation in the development of new drug formulations. This may not be surprising given that more than a third of the drugs listed in the United States Pharmacopoeia are either poorly soluble or insoluble in water. Intranasal (IN) administration may achieve an effective therapeutic brain drug concentration, through the nose-brain pathway, that allows direct delivery to the cerebrospinal fluid.4,5 Therefore, the IN route can diminish drug distribution to non-targeted sites and decrease systemic adverse effects.2,6,7 Despite these advantages, IN delivery suffers from some restrictions such as poor drug permeability from nasal mucosa, mucociliary clearance, low drug retention time and nasomucosal toxicity.8,9 To overcome these restrictions, various colloidal drug nanocarriers (NCs) especially the lipid-based ones have been utilized to improve the drug permeability and absorption.7,10,11 The rapid nasal mucociliary clearance, that results in low absorption and poor bioavailability, could be overcome by development of mucoadhesive in situ nasal gelling drug delivery systems that prolong the retention time and control the drug delivery via this route.12 Such formulations were intended to help IN-drug delivery but, the clinical success of IN therapy is limited owing to the irritation of the nasal mucosa or to the frequent and high dose of the formulation required. Hence, further development of suitable lipid-based NCs to overcome these barriers is needed.
Vinpocetine (VNP), derived from the natural vinca alkaloid vincamine, is widely utilized as a vasodilator and a nootropic agent.1,2 VNP is used for improving memory and cerebral metabolism in cerebrovascular and age-related memory disorders.3,4 The extensive first pass drug metabolism and low aqueous solubility hinders the full utilization of VNP oral dose because of its low oral bioavailability.5 Due to the bioavailability problems with oral delivery of VNP, alternative and effective formulations for VNP delivery are needed, particularly to enhance delivery to the brain.